The present invention relates to an apparatus for supporting loads, for rolling lateral movement in all directions across and for rotation about a vertical axis on a supporting surface, and more particularly, to a caster assembly comprising a plurality of caster units mounted in a spaced array.
Many temporary load supporting and traverse units are currently available. One such unit is known as a roller skid and comprises a frame having a plurality of cylindrically shaped rollers mounted for rotation thereon. In use, the load is elevated by means not associated with the roller skids. Three or more of the roller skids are then placed under the load at predetermined locations so that the load is evenly distributed to each of the roller skids. The load is then lowered onto the skids for traverse. In their simplest form, skids are satisfactory for movement of a load in a relatively straight line. However, when the load must be turned, the load must again be re-elevated, the roller skids turned so as to be aligned in the desired traverse direction, and the load again lowered onto the skids. Turntables are provided for interposition between the roller skids and the load so that the roller skids can be manually turned relative to the load for movement in an alternate direction. With such transportation devices, it is very difficult to turn the load itself relative to the first direction of traverse.
Other transport devices are available that do provide the desired ability to turn the load itself rather than to merely change the direction of traverse. Such devices include pressurized air cushion support devices and the like. For certain applications such devices are more than adequate. However, for movement of relatively small loads on the order of one to five tons, the capital investment required for such devices become prohibitive. These devices also require a continuous supply of pressurized fluid at a substantial flow rate and a sealed and extremely smooth surface upon which to operate efficiently.
It is therefore an object of the present invention to provide a load support and traverse assembly that is relatively inexpensive to manufacture, that can support substantial loads, that has the capability to lift and hold a load from the floor without the use of external or auxiliary load lifting means, and that can be used to move a support load in any given direction as well as to orient the load for traverse in an infinite number of directions without lowering and reelevating the load and without the use of turntables or the like.
Further objects of the present invention are to provide a load supporting caster assembly including a multiple array of caster units, each of which support a distributive share of a given load without horizontal prealignment; to provide such an assembly with the capability of equally loading caster units as they traverse an irregular surface so as to prevent overloading of any individual caster; and to provide such an assembly with a resilient mounting so as to cushion the supported load from shocks that it might otherwise receive as it is being transported over irregularities in a supporting surface.